Typical computer systems, especially computer systems using graphical user interface (GUI) systems, such as Microsoft WINDOWS, are optimized for accepting user input from one or more discrete input devices, such as a keyboard for entering text and a pointing device (e.g., a mouse with one or more buttons), for driving the user interface. The ubiquitous keyboard and mouse interface provides for fast creation and modification of documents, spreadsheets, database fields, drawings, photos and the like. However, in some respects, there is a significant gap in the flexibility provided by the keyboard and mouse interface as compared with the non-computer (i.e., conventional) pen and paper. With conventional pen and paper, a user may edit a document, write notes in a margin, and draw pictures and other shapes, and the like. In some instances, a user may prefer to use a pen to mark-up a document rather than review the document on a computer screen because of the ability to freely make notes outside of the confines of the keyboard and mouse interface.
Some computer systems permit users to draw on a screen. For example, the Microsoft READER application allows users to add electronic ink (also referred to herein as “ink” or “digital ink”) to a document. The system stores the ink and provides it to a user when requested. Other applications (for example, drawing applications as known in the art associated with the Palm 3.x and 4.x and PocketPC operating systems) permit the capture and storage of drawings. Also, various drawing applications, such as Corel Draw, and photo and editing applications, such as Photoshop, may be used with stylus based input products, such as the Wacom tablet product. These drawings include other properties associated with the ink strokes used to make up the drawings. For instance, line width and color may be stored with the ink. One goal of these systems is to replicate the look and feel of physical ink being applied to a piece of paper.
While computer systems that accept electronic ink are known, at present time their availability and usefulness, in at least some respects, are somewhat limited. To further increase their availability and usefulness, application programs must include code that allows interaction and interfacing with the electronic ink. Accordingly, an application programming interface (“API”) that allows code writers to readily, flexibly, and consistently interact and interface with various different groupings of ink would be very useful to those who wish to write code for application programs that interact in some manner with electronic ink.